Open Source Tenable Nessus Alternatives
A curated collection of the 1 best open source alternatives to Tenable Nessus.
The best open source alternative to Tenable Nessus is ProjectDiscovery. If that doesn't suit you, we've compiled a ranked list of other open source Tenable Nessus alternatives to help you find a suitable replacement.
Tenable Nessus alternatives are mainly Monitoring & Observability but may also be Threat Detection & Response. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Tenable Nessus.
A template-driven vulnerability scanner that runs YAML detection recipes across HTTP, DNS, TCP and more, at scale from the command line.
Nuclei is a vulnerability scanner whose detection logic lives in YAML files rather than in the scanner itself. A template names the requests to send and the conditions that confirm a finding, which is how the project pursues zero false positives, by reproducing the steps an attacker would take instead of matching a banner.
Templates come from thousands of contributing security professionals and live in their own repository, so coverage of trending vulnerabilities arrives without waiting for a release. Scanning runs in parallel with request clustering, and one binary handles TCP, DNS, SSL, WHOIS, JavaScript and code protocols. It installs with go install and needs Go 1.24.2 or newer.
Its command line gives fine control over what actually runs.
- Template filtering: select or exclude by tag, author, severity, template id or protocol type.
- Input formats: targets from a list, Burp output, JSONL, YAML, OpenAPI or Swagger definitions.
- Automatic scans: technology detection maps a target to the tags worth running against it.
- Custom templates: write your own, validate them, and sign them so unsigned ones can be refused.
- Pipeline integration: run it as a CI step for detection and regression testing, pushing results to Jira, Splunk, GitHub, Elastic or GitLab.
The maintainers warn that the project is in active development and that breaking changes land with releases, so read the changelog before upgrading. They also state plainly that it is built as a standalone CLI tool and that running it as a service carries security risks. A free cloud tier stores findings and templates.
